1. Field of the Invention
The present invention relates to a road shoulder collapse risk monitoring system that presents information on a risk of a road shoulder collapsing when a motor vehicle is brought close to the shoulder. The invention also relates to a transport vehicle including the system.
2. Description of the Related Art
While driving a vehicle, the driver may be required to bring the vehicle close to the shoulder of the road for purposes such as steering clear of oncoming vehicles, on-road obstructions, and other objects. JP-2004-302609-A describes a technique for ensuring operational safety during such an approach to the shoulder by monitoring the distance between the vehicle and the shoulder or an on-road obstruction via a vehicle-mounted camera or the like and if the distance decreases below a predetermined value, alerting the driver to that effect.
During the approach to a shoulder sloped downward from the road surface, since a collapse of the shoulder due to weak ground is likely, it may not always suffice to determine safety only by means of the distance between the vehicle and the shoulder or the like, as in the above conventional technique. This becomes a problem particularly when the vehicle travels past other vehicles on a road that is too narrow for the driver to avoid close proximity to the shoulder. In addition, even if the distance to the shoulder is long enough, on an unpaved road provided primarily in private land and having no reinforcing measures taken for the slope of the shoulder, the possible collapse of the shoulder due to vehicle weight is estimated to result in the vehicle getting stuck in the shoulder. The conventional technique is not designed so as to alert the driver to a risk of such a shoulder collapse. The conventional technique has a problem, therefore, in that although the technique may be effective for preventing the vehicle from obviously slipping outward from the shoulder, too great an advantageous effect cannot be obtained against a collapse risk of the shoulder itself.
An object of the present invention is to provide a shoulder collapse risk monitoring system capable of alerting a driver to a risk of a road shoulder collapse during approach operations to the shoulder.